The present invention relates to a probe apparatus and a method for polishing a probe.
Conventionally, a probe apparatus 10 of the type shown in FIGS. 9 and 10 is used for electrical inspection of IC chips that are formed on a semiconductor wafer (hereinafter referred to simply as "wafer"), for example. As shown in these drawings, this apparatus 10 comprises a cassette carrying section 11 in which a cassette C stored with wafers W is placed, a loader section 12 including a transportation mechanism (not shown) for transporting each wafer W delivered from the cassette C in the section 11, a prober section 13 for inspecting the wafer W transported by means of the transportation mechanism, a controller 14 for controlling the prober section 13 and the loader section 12, and a display unit 15 that doubles as a control panel for operating the controller 14. The loader section 12 is provided with a sub-chuck (not shown), whereby the wafer w is pre-aligned on the basis of its orientation flat. The pre-aligned wafer W is transported to the prober section 13 by the transportation mechanism. The prober section 13 is provided with a main chuck 16 movable in the X-, Y-, and Z-directions and the .theta.-direction (direction of rotation around the Z-axis) and capable of carrying the wafer W thereon, an alignment mechanism 17 including a CCD camera, an alignment optical system or the like for accurately aligning the wafer W on the main chuck 16 in a position for inspection, and a probe card 18 having a probe 18A for electrically inspecting the wafer W aligned by means of the alignment mechanism 17. A swingable head plate 19 is mounted on the top face of the prober section 13. The probe card 18 is fixed to a center aperture of the head plate 19 by means of an insert ring 19A. A test head 20 is rotatably located on the prober section 13. In electrically inspecting the IC chips on the wafer W, the probe card 18 and a tester (not shown) are connected electrically to each other through the test head 20, and a given inspection signal from the tester is transmitted to the IC chips of the wafer W on the main chuck 16 via the probe card 18.
A card transportation arm (not shown) is provided on the front side of the prober section 13. This transportation arm transports the probe card 18 with a card holder to a position right under the insert ring 19A of the head plate 19. Normally, the card transportation arm is contained in a cover 21 that is attached to the front of the prober section 13. In changing the probe card 18, the card transportation arm is raised to a level position and then turned to the position right under the insert ring 19A with the cover 21 lowered. The transportation arm, thus positioned right under the ring 19A, receives the probe card 18 that is automatically disengaged from the ring 19A, and transports it to the front of the prober section 13. At this time, an operator removes the card 18 on the card transportation arm, and places a new probe card 18 on the transportation arm. Thereafter, the transportation arm, carrying the new card 18 thereon, is turned again to the position right under the insert ring 19A.
In the electrical inspection of the wafer W, the wafer W on the main chuck 16 and the probe 18A are aligned with each other by means of a drive mechanism, such as a moving table that is movable in the X- and Y-directions, for example. Thereafter, the main chuck 16 is overdriven upward, whereupon a natural oxide film (e.g., aluminum oxide film) formed on the surface of an electrode pad (formed of, e.g., aluminum) of the wafer W is scraped off by means of the probe 18A, so that the probe 18A and the electrode pad can be securely brought into electrical contact with each other. If this inspection is repeated, however, oxide aluminum, an electrical insulator, may adhere to the probe 18A, or the distal end of the probe 18A may wear, possibly hindering the inspection thereafter. Conventionally, therefore, a steady inspection is secured by polishing the probe 18A in a manner such that a polishing plate, which is attached to a part of the main chuck 16, is brought into contact with the probe 18A, and that the chuck 16 is moved up and down.
In general, the polishing plate is used semi-permanently without replacing. Accordingly, its repeated use leaves filings thereon, which float as particles, possibly exerting a bad influence on the inspection, as the main chuck 16 moves. Although the filings are removed from the polishing plate by suction, therefore, production of the particles cannot be fully prevented by that alone. The influence of the particles becomes more serious as the IC chips are microminiaturized, in particular. As the polishing plate is repeatedly used, it is gradually worn at its polishing surface and its polishing ability gradually decreases. Naturally, this problem can be solved by changing the polishing plate on each occasion. According to the conventional arrangement, however, the polishing plate can be changed only after evacuating the test head 20 from the probe apparatus 10 and swinging the head plate 19 open to expose the prober section 13. Since the polishing plate is attached to the main chuck 16 by means of screws or the like, moreover, its replacement is very complicated and takes a lot of time.